Do away with (something)
To stop something, to get rid of something. The company will do away with their policy of working one weekend a month.
Do credit to (someone)
To add to someone's reputation. The woman's graduation thesis did credit to her hard work and patience.
Do in (someone) / do(someone) in
To make someone tired, to exhaust someone. I was done in after I finished the marathon.
Do in (something) / do(something) in
To ruin or destroy something. The boy quickly did in the new shoes that he had received for his birthday.
Do justice to (something)
To do something well, to represent something accurately. The painting of my grandfather does not do justice to his extremely good looks.
Do lunch
To meet someone for lunch. I plan to do lunch with my friend tomorrow.
Do one`s best
To try to do something as well as one can. I tried to do my best on the exam.
Do one`s bit
To make one's expected contribution to a group project. Our teacher did his bit to help plan for the party.
Do one’s duty
To do one's job or what is expected of one. The guard was doing his duty when he began to ask the customer questions.
Do one`s part
To make one's expected contribution to a group project. Everybody had to do their part to make the meeting a success.